Monika Maeckle is a butterfly evangelist, caterpillar wrangler, Master Gardener, Monarch tagger and curious student of nature who loves the whole life cycle. You can reach her at butterflybeat@gmail.com.

Note: This is an mySA.com City Brights Blog. These blogs are not written or edited by mySA or the San Antonio Express-News. The authors are solely responsible for the content.

Monarch Butterflies Get all the Press, But Eastern Swallowtails are Year-Round Butterfly Stars

Monarch butterflies get all the glory this time of year with their unique migration through town en route to their winter roosting spot in Michoacan, Mexico. But another gorgeous creature captures our attention as we mark the first days of Fall: The Eastern Swallowtail.

One reader emailed, to ask about a “beautiful black and blue butterfly” depositing eggs on her parsley

plant. Her visitor was a member of the Swallowtail family. Several species are found in Texas.

Monarchs and Swallowtails are native to the area. Unlike Monarchs, however, Swallowtails are here year-round. And their caterpillars are much less picky about their meals than Monarchs.

Swallowtail caterpillars will chow down on fennel, parsley, rue and dill–all of which grow easily in the Fall garden and also supply cooks with ready-to-snip fresh herbs. In San Antonio, I find fennel and flat leaf Italian parsley are easy-to-grow, and the best choice for attracting Swallowtails. A friend in Austin had Swallowtail caterpillars covering her rue plant, so it often depends on your yard.

The four Swallowtail caterpillars pictured here were found on a fennel plant I planted in February and which, typically, I would have pulled and composted. Given the tough freezes this winter, I elected to let it grow.

My reward was a fabulous Swallowtail habitat that kept me busy all summer with the voracious eaters who consume almost every part of the plant. Swallowtail caterpillars eat the leaves, stems, and flowers. They shun only the seeds, thus doing their part to ensure a resupply for the next hungry generation.

The caterpillars are an endless source of entertainment with their constant munching, amazing transformation between stages, and their acrobatic contortions. In the first stage, they disguise themselves as bird excrement to fool predators. Later, they are able to project little orange “antlers,” osmeterium. When touched, these strange tentacles give off a distinct aroma that is meant to turn off hunters. Kids love this. Eventually, the fat “cats” transform into lovely green-and-yellow or brown chrysalises, depending on the time of year and their surroundings.

According to the International Butterfly Breeders Association, the largest and oldest professional butterfly farming trade group, Swallowtails are notoriously unpredictable in their life cycle. While the caterpillar stage can last up to two weeks, they remain in their chrysalis anywhere from 10 days to several months.

The caterpillars also wander around quite a bit, searching for a place to spin their chrysalis, which they attach to a stick, stem or other sturdy surface with a silk thread. I’ve had Swallowtails make their chrysalises yards from the host plant where they resided as caterpillars. One hatched under my couch.

Now is an excellent time to plant fennel, Italian parsley, rue or dill in your garden. This will provide you with several months of enjoyment as you witness Swallowtails progress through their life cycle before falling temperatures signal the arrival of the winter Butterfly Break. Area nurseries have plenty of Swallowtail friendly herbs in stock. Plant them now and let them grow through Spring. Your prize will be many Swallowtail visitors.